/*
 * Created on Apr 27, 2013
 * Created by Paul Gardner
 * 
 * Copyright 2013 Azureus Software, Inc.  All rights reserved.
 * 
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License only.
 * 
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307, USA.
 */

package com.aelitis.azureus.core.util;

import java.util.AbstractSet;
import java.util.Collection;
import java.util.IdentityHashMap;
import java.util.Iterator;

public class IdentityHashSet<E> extends AbstractSet<E> {
    private IdentityHashMap<E, Object> identity_map;

    public IdentityHashSet() {
        identity_map = new IdentityHashMap<E, Object>();
    }

    public IdentityHashSet(Collection<? extends E> set) {
        identity_map = new IdentityHashMap<E, Object>(Math.max((int) (set.size() / .75f) + 1, 16));

        addAll(set);
    }

    public int size() {
        return (identity_map.size());
    }

    public boolean contains(Object entry) {
        return (identity_map.containsKey(entry));
    }

    public boolean add(E entry) {
        return (identity_map.put(entry, "") == null);
    }

    public boolean remove(Object entry) {
        return (identity_map.remove(entry) != null);
    }

    public void clear() {
        identity_map.clear();
    }

    public Iterator<E> iterator() {
        return identity_map.keySet().iterator();
    }
}